Tongue function and its influence on masticatory performance in patients treated for oral cancer: a five-year prospective study

Abstract

Purpose The purpose of this study was to observe the impact of oral oncological treatment, including the recovery of several tongue functions (force, mobility, and sensory functions), and to determine the influence of these functions on masticatory performance. Materials and methods Masticatory performance and tongue force, mobility, and sensory functions were determined in 123 patients with oral cavity cancer. The assessments were performed 4 weeks before treatment and 4 to 6 weeks, 6 months, 1 year, and 5 years after treatment. Generalized estimation equations and mixed model analyses were performed, correcting for previously identified factors in the same population. Results A significant deterioration in tongue mobility and sensory function was observed in patients with mandible and tongue and/ or floor-of-mouth tumors. Better tongue force and sensory function (thermal and tactile) positively influenced masticatory performance, and this effect was stronger where fewer occlusal units were present. The effect of both the tongue force and maximum bite force was weaker in dentate patients in comparison with patients with full dentures. A web-based application was developed to enable readers to explore our results and provide insight into the coherence between the found factors in the mixed model. Conclusions Tongue function deteriorates after oral oncological treatment, without statistically significant recovery. Adequate bite and tongue forces are especially important for patients with a poor prosthetic state. Patients with sensory tongue function deficits especially benefit from the presence of more occluding pairs.

Validation of masticatory function and related factors in maxillectomy patients based on the concept of "oral hypofunction": A retrospective cross-sectional study

“…We interpret the present results as significant findings, although future studies with larger sample sizes should focus more specifically on maxillectomy patients and their condition. A previous study reported that MTP or tongue force could influence masticatory function [34], whereas the present study could not detect a significant association. The potential reasons for this are as follows: 1) while the wide distribution of MOF was observed, only a narrow distribution of MTP was noted in the present study, 2) the sample size in the present study was comparatively smaller than that in the previous study, and 3) the previous study included not only maxilla tumor, but also mandible and tongue and/or floor-of-mouth tumors.…”

“…Multiple regression analysis indicated that MOF can be a potential predictor of masticatory function. This finding is supported by previous studies in elderly patients and in maxillectomy patients [8,10,12,14,34] and might be explained by specific reasons. Multiple factors such as teeth, occlusal contacts, prostheses, and muscles are involved in mastication [19].…”

“…In other words, it might be important to arrange oral conditions, including prostheses, to create occlusal force. It has also been reported that adequate occlusal force could play a pivotal role in mastication in patients with a poor prosthetic state [34]. We interpret the present results as significant findings, although future studies with larger sample sizes should focus more specifically on maxillectomy patients and their condition.…”

“…MTP, tongue muscle, and its function have been known as factors associated with masticatory function and MOF [12,26,[31][32][33]. Tongue function, including maximum tongue force after oral cancer treatment, was assessed in a previous study [34]. It demonstrated that tongue functions, including tongue force or MTP, deteriorate after oral oncological treatment.…”

“…Ideally, all oral functions based on the concept of "oral hypofunction" in particular, tongue functions, should have been investigated in this study; however, the number of predictor variables for multiple regression analysis was limited by the sample size. According to a previous study that demonstrated the important role of tongue force (MTP) in masticatory function in patients who had undergone maxillectomy [34], we decided to adopt MTP as a predictor variable. This meant that the sample size of the present study was insufficient, and future studies with larger sample size should explore oral functions and their associations in maxillectomy patients.…”